I wanted to post this out here as I think I finally found my solution to a very obscure problem.
I have a desktop beast for gaming (AMD Ryzen 9, 7900XT, 64GB ram) with a primary 32” 4K monitor and a secondary 27” 2.5K monitor. I use Manjaro KDE Wayland.
I load Steam on the secondary and game on the primary.
While playing Doom: Dark Ages on the 32” 4K, I would play for awhile and while playing the monitor would enter sleep mode. Sometimes it would come back in 5 seconds, sometimes the game would move over to the other monitor and sometime it would just stay sleeping and the only way to recover was to pull up a terminal on the secondary screen and do “shutdown -h now” and reboot.
I scoured the web thinking others would have seen this problem but found literally nothing similar. I was thinking, kernel issues, mesa drivers, proton, what could it be? Looking at logs I just was not finding anything. Starting Steam from terminal, I was not finding anything.
Finally I thought my GPU has 2 display ports. Does it matter which monitor is connected to which port? Since I have the 32” flagged as the primary in KDE’s desktop settings, does it want it to be in a specific DP port on the GPU? Swapping the ports is a pretty easy test, so I swapped the cables in the GPU.
Voila! I have been gaming for a week and this very irritating bug seems to be gone. It drove me nuts when I was in the middle of a ferocious demonic battle and the screen would go black.
I am not 100% sure it is solved, but it sure seems to be. I have 7 gaming sessions in a row with no glitches. I used to consider myself very lucky when I got 2 in a row with no glitches (i.e. it happened a lot).
Another perhaps clue I missed is when I would boot the machine, even though I had the 32” setup as my primary in KDE, when SDDM would appear and I did my password, it always took place on the 27” monitor, almost as they were fighting for which one was truly primary based on which DP port they were connected to on the GPU.
Anyone with technical knowledge who could speak to this? Did I likely find my problem? I am only going on anecdotal evidence and a relatively small window of positive experience here, but it seems very promising.
Thank you to the Manjaro team and Manjaro community. This experience has been so overwhelmingly positive compared to other OS’s. I actually enjoy my computers again.